None.
This invention relates to latches that are flush or near flush when mounted in a door or frame. Typically, the latch handle is contained with this low profile while not in use, but may be extended in some way to provide access to an operator. Once extended, the handle may be operated to open the door.
One example of such a generally flush mounted latch assembly is U.S. Pat. No. 5,450,735, issued to Takanobu Esaki, et al. of Tokyo, Japan on Sep. 19, 1995. Esaki discloses a pull-out-and-rotate type latch assembly. When locked, the latch handle lies nearly flush with the surrounding housing and door. When unlocked, the handle may be pivoted to an extended position and turned thereby turning a latching plate at the end of a spindle, allowing the door to be opened. Another example of a flush type latch assembly is U.S. Pat. No. 5,457,971, issued to Kenichi Yamada of Tokyo, Japan on Oct. 17, 1995. Yamada discloses a push-button spring-loaded rotary type latch assembly in which a torsion spring urges the handle into an extended position when a push-button is depressed.
In both Esaki and Yamada, the key cylinder is mounted in the handle and the shaft and latching plate can only rotate. Since the key cylinder is mounted in the handle, the length of the handle is dictated in part by how many fingers must fit between the key cylinder and the handle""s pivot. Since the latching plate in each does not move axially but only rotates, it does not additionally cinch the door to the frame upon closing. Also, a separate push button mechanism is utilized to release the handle.
What is needed is a push-button type flush mounted latch assembly wherein the push button mechanism is greatly simplified. Additionally, what is needed is such a latch in which the key cylinder may work just as well if mounted in the housing rather than the handle. What is further needed is a latch assembly that causes the latching pawl to both rotate and draw in upon closing so that the door is cinched tightly to the frame.
An object of the present invention is to provide a door latch assembly having a latch housing and handle that are substantially or near flush with the surrounding outer surface of the door in which they are mounted when the latch assembly is in its closed position.
A further object of the present invention is to provide such a latch assembly that utilizes a push-button mechanism in order to release at least a portion of the handle to be pivoted to an extended position and grasped and turned by an operator. Another object of the present invention is to provide such a flush mounted latch in which the push button unit comprises a greatly simplified configuration. Another object of the present invention is to provide such a flush mounted latch in which the locking cylinder itself may operate as the push button for releasing the handle.
It is a further object of the present invention to provide a locking shaft that is slidably connected to the handle so that the locking shaft may move axially as well as rotate at the same time so that a pawl member on the end of the locking shaft may cinch down on the frame to create a tight closure between the door and frame.
These objects are accomplished by the present invention of a latch assembly having a latch housing and handle that are substantially or near flush with the surrounding outer surface of the door in which they are mounted when the latch assembly is in its closed position. The latch assembly utilizes a greatly simplified push-button mechanism in order to release at least a portion of the handle, which then pivots to an extended position and grasped and turned by an operator. A spindle and latching pawl are slidably connected to the handle and bound by a camming surface in the latch housing so that the spindle and latching pawl moves both axially and rotationally at the same time so that, upon closing, the pawl will cinch down on the frame to create a tight closure between the door and frame.
Other aspects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed descriptions of preferred embodiments when considered in conjunction with accompanying drawings, which illustrate, by way of example, the principles of the invention.